Increasing orthostatic stress impairs neurocognitive functioning in CFS with POTS

[RustyJ]

Increasing orthostatic stress impairs neurocognitive functioning in Chronic Fatigue Syndrome with Postural Tachycardia Syndrome.

Ocon AJ, Messer Z, Medow M, Stewart J.
Clin Sci (Lond). 2011 Sep 15. [Epub ahead of print]

Abstract
Chronic Fatigue Syndrome (CFS) is commonly co-morbid with Postural Tachycardia Syndrome (POTS). Individuals with CFS/POTS experience unrelenting fatigue, tachycardia during orthostatic stress, and ill-defined neurocognitive impairment, often described as mental fog. We hypothesized that orthostatic stress causes neurocognitive impairment in CFS/POTS related to decreased cerebral blood flow velocity (CBFV).

16 CFS/POTS and 20 control subjects underwent graded tilt table testing (at 0, 15, 30, 45, 60, and 75) with continuous cardiovascular, cerebrovascular, and respiratory monitoring and neurocognitive testing using a N-back task at each angle. The N-back task tests working memory, concentration, attention, and information processing. The N-back imposes increasing cognitive challenge with escalating (0, 1, 2, 3, and 4-back) difficulty levels. Subject dropout due to orthostatic presyncope at each angle was similar between groups.

There were no N-back accuracy or reaction time differences between groups while supine. CFS/POTS subjects responded less correctly during the N-back and had greater normalized reaction time at 45, 60, and 75. Further, at 75 CFS/POTS subjects responded less correctly and had greater normalized reaction time than controls during the 2, 3, and 4 back tests. Changes in CBFV were not different between the groups and were not associated with N-back scores.

Thus, we concluded that increasing orthostatic stress combined with a cognitive challenge impairs the neurocognitive abilities of working memory, accuracy, and information processing in CFS/POTS, but that this is not related to changes in CBFV. Individuals with CFS/POTS should be aware that orthostatic stress may impair their neurocognitive abilities

http://www.ncbi.nlm.nih.gov/pubmed/21919887

There were no N-back accuracy or reaction time differences between groups while supine.

In my case, once I reach a point where I am affected by orthostatic stress, I find relief, but do not go back to normal when I lie down - it generally takes hours. This is an important distinction which is not investigated. The point being that in some instances of affected blood flow to the brain ie low blood pressure, when the patient lies down, they immediately go back to being normal.

 

[Dolphin]

http://www.ncbi.nlm.nih.gov/pubmed/21919887



In my case, once I reach a point where I am affected by orthostatic stress, I find relief, but do not go back to normal when I lie down - it generally takes hours. This is an important distinction which is not investigated. The point being that in some instances of affected blood flow to the brain ie low blood pressure, when the patient lies down, they immediately go back to being normal.

Interesting observation.

Two quick ones from me:
- when my heart beat gets above a certain point/I get "excited"/"agitated", it can be hard to get right back to a fully relaxed state.

- with exercise with the condition, even if one lies down afterwards, we don't recover as quickly as other people; perhaps the effect is similar with standing.

 

[bertiedog]

Interesting observation.

Two quick ones from me:
- when my heart beat gets above a certain point/I get "excited"/"agitated", it can be hard to get right back to a fully relaxed state.

- with exercise with the condition, even if one lies down afterwards, we don't recover as quickly as other people; perhaps the effect is similar with standing.

Yes this is my experience too, once my heart starts getting too fast then the energy just runs away from my legs. Heat and doing too much when I am not feeling very good will also do this. This is the reason I take at least 20 mg Propananol each day, it is very helpful.

One other thing that seems to help a bit is to eat some carbs and protein when my heart starts going too fast.

Pam

 

[ahimsa]

True, but one line did make me laugh

Thanks for posting this, RustyJ! I am glad they have done the science to demonstrate something that has been experienced by so many patients. Plus, it's interesting that the test did not show a correlation between cognitive dysfunction and decreased cerebral blood flow velocity (CBFV). (Is decreased CBFV the same as hypoperfusion?)

But I guess I'm a bit punchy tonight because the following line in this abstract, although perfectly true, made me laugh out loud:

Individuals with CFS/POTS should be aware that orthostatic stress may impair their neurocognitive abilities.

Wow, is this the understatement of the year, or what? I think most of us who live with this illness already know this.

Yeah, "orthostatic stress", or what we patients would likely call "standing" (and some other activities such as sitting up straight for too long), does indeed "impair [my] neurocognitive abilities." In fact, if you ask me a question while I'm standing up you'll mostly likely get one of two responses:

1) I'll get that "deer in the headlights" look while I try desperately to figure out what you are asking me. This happens routinely if a store employee innocently comes up to ask me, "May I help you?" Luckily, I can generally figure out what to do (sit down on my folding chair) even if I can't figure out what to say. Fortunately, my husband has learned to say, "Please sit down, I need to ask you something." (He's so patient and amazing!)

2) If it's a good day then I can manage to say, "Wait, let me sit down so I can think." Yes, I use those exact words.

So, yeah, I've figured out this connection between standing and lack of thinking. But scientific confirmation is always a good thing!

PS. My diagnosis is actually a type of OI called NMH (Neurally Mediated Hypotension), not POTS. However, after 21 years I think I may have both NMH and POTS. My heart rate when standing is a lot higher than it used to be. I didn't realize it until last year when I took a couple weeks of BP readings while standing, first thing in the morning, before any medications or food. I did it to see what my BP was doing but of course the monitor also shows heart rate. I was surprised to see my heart rate readings were so high (e.g., anywhere from 115 to 150 BPM after standing for about a minute, just long enough for the BP monitor to get a reading).

 

[Dolphin]

I just read the full text.
I don't have a good knowledge of biology but was able to understand this pretty thoroughly, I think (i.e. it's not too difficult, although I have learned a bit from reading in the field).
Most of the data are in the figures/graphs, which is also spelled out quite well in the text if anybody has difficulty understanding such figures/graphs (however, figures/graphs don't deal with interaction effects). (As well as being spelled out in the results section, the results are also repeated in the discussion section which has individual sections and probably covers all that most people might need).

Apart from one mention that deconditioning might be one reason for higher heart rates at baseline, there was no other discussion of that and no mention at all of graded exercise therapy, CBT, etc i.e. I'd feel reasonably safer given this to doctors than some papers.

The fairly consistent pattern of abnormalities was nice.

All in all, I enjoyed reading it.

 

[Dolphin]

No major evidence of NMH/similar in this group

No major evidence of NMH/similar in this group (i.e. similar to controls)

Subject dropout per angle

Figure 1 shows the survival curves or the ability of
subjects to complete each successive tilt angle, for
CFS/POTS and control subjects individually, as well as
a combined curve of both groups. All 16 CFS/POTS
and 20 control subjects completed the 0? and 15? tilts. A
total of 15 CFS/POTS and 20 control subjects completed
the 30? tilt. A total of 14 CFS/POTS and 18 control
subjects completed the 45? tilt. A total of 13 CFS/POTS
and 15 control subjects completed the 60? tilt. Seven
CFS/POTS and 11 control subjects completed 75?.
KaplanMeiers analysis using the logrank test found that
survival throughout tilt was not significantly different
between groups.

MAP (=mean arterial pressure)

As shown in Figure 4(A), when MAP was analysed
as a function of tilt angle, there were no significant
differences comparing CFS/POTS subjects with controls.
Figure 4(B) shows that, when MAP was analysed as
a function of the n-back difficulty level, there were
no differences between these two groups. In addition,
there were no significant differences when the data were
evaluated as a function of group, angle and n-back. Thus
MAP was relatively maintained throughout tilt at all
angles in both the CFS/POTS and control subjects and
was not affected by the n-back testing.

 

[xchocoholic]

I noticed that when my pots hits, 10 minutes after standing, that many times I also have a petite mal and sob. I'm not sure
how many of us do that but this means we won't recover right away. It typically takes me an hour
to recover to feeling "normal", but I've yet to figure out why sometimes it takes longer.

When I came down with h pylori and parasites at the same time no less, my oi was so bad I could
barely stand up at all .. now that i've treated for these I'm back to my previous "not so healthy" level
Tc .. X

 

[Tom Kindlon]

This shows again how being more upright has a negative effect, but not for healthies.

Also 4-back is the hardest cognitive test and 0-back is the easiest. So the effect is most pronounced, the harder the test. What is being measured is reaction time/response time. So patients were gradually getting more and more worse compared to the healthies, the more challenging the task.

 

[Tom Kindlon]

Another figure. The text underneath explains it.

n-back are cognitive tests which get harder the higher n is.
Tilt angle is the angle they were tilted. 0 represents being flat and 90 means being full upright.